The invention relates to an apparatus for playing back information digitally stored on an optical record carrier, comprising
a control circuit by means of which the display and/or reproduction of information, particularly video and/or audio information, is selectable and/or controllable,
a parameter memory for storing navigation parameters during playback of a record carrier.
An apparatus of this type is known from, for example, WO 98/09290. This known apparatus is provided for playing back digital video record carriers. To control the display of the audio and/or video program, the known apparatus has navigation commands and navigation parameters. Generally, those parameters are understood to be navigation parameters whose information is stored by the playback apparatus during the playback process. The navigation parameters comprise, for example, parameters to which a predetermined function is assigned and also parameters which can be freely used by the provider and are, for example, usable for modifying the behavior of the playback apparatus or for storing the user-performed operations, decisions and/or wishes. Navigation commands and navigation parameters are the basis for providers of record carriers for creating different title structures. The providers can use the navigation commands and navigation parameters for adjusting or changing the status of the playback apparatus, for example, for implementing a parental control system which denies children access to predeterminable video programs.
For example, logic AND and OR combinations, comparative operators such as EQUAL/UNEQUAL or register commands are available as navigation commands.
The provider can define simple and complex branch structures in a title by means of the navigation commands and the navigation parameters.
The navigation parameters of record carriers based on the DVD standard are set to zero at the start and the end of a playback process of a record carrier.
It is art object of the invention to provide an apparatus of the type described in the opening paragraph, rendering playback of navigation parameters assigned to a record carrier usable for playback at a later stage.
According to the invention, this object is achieved in that the apparatus comprises a first non-volatile memory which is controllable by means of the control circuit, in that the first non-volatile memory is provided for storing navigation parameters, in that the navigation parameters are stored together with record carrier identification information allowing assignment of the navigation parameters to a record carrier, in that, at the start of a playback process of a record carrier, the navigation parameters assigned to said record carrier are readable from the first non-volatile memory and writable into the parameter memory.
The navigation parameters assigned to a playback process can thus be stored in the first non-volatile memory and made available for playback at a later stage. During storage in the first non-volatile memory, the navigation parameters are provided during storage with record carrier identification information, for example, a record carrier identification number. This record carrier identification number is stored at a predeterminable location on the record carrier. At the start of a playback process, the control circuit checks whether the relevant record carrier is provided with record carrier identification information. If the relevant record carrier is provided with record carrier identification information, the control circuit checks whether navigation parameters corresponding to this record carrier identification information are stored in the first non-volatile memory. If this is the case, the navigation parameters are read from the first non-volatile memory and written into the parameter memory. Alternatively, an access path to these navigation parameters can be formed. If no navigation parameters relating to record carrier identification information have been stored in the first non-volatile memory, the written record carrier identification information is preferably written by the control circuit into the first non-volatile memory, or a relevant access path is formed. Both a RAM memory and a register memory may be used as a parameter memory.
The apparatus according to the invention has the advantage that, by means of storage of the navigation parameters, an exchange of information between different playback processes is possible. The exchange of information may be realized both between different playback processes of one and the same record carrier. It is also possible to utilize the playback navigation parameters of a first record carrier for playback of a second record carrier. This is particularly advantageous for series of record carriers, for example for a training course comprising several record carriers.
The embodiment of the invention as defined in claim 2 has the advantage that, by means of the interface, an exchange of data relating to the navigation parameters with an external input and/or output apparatus is possible. On the one hand, the playback process of the record carrier can thereby be changed and influenced by means of an external input apparatus. On the other hand, the navigation parameters stored in the first non-volatile memory can be externally read and evaluated. It is particularly possible to provide predetermined navigation parameters for playing back a record carrier, i.e. the playback mode of this record carrier and, for example, given playback sequences can be fixed in advance in that, as defined in claim 11, navigation parameters determining the playback process for the record carrier are stored in advance in the first non-volatile memory. For example, it is possible to place playback apparatuses at different locations in a museum and store different navigation parameters for the same record carrier. This renders it possible that the same record carrier is played back on the different playback apparatuses, i.e. different playback apparatuses play, for example, different chapters, sections or contents on the same record carrier.
The advantageous embodiment of the invention as defined in claim 3 has the advantage that the navigation parameters stored in the first non-volatile memory are updated in a predeterminable manner.
By means of the advantageous embodiment of the invention as defined in claim 4, the temporal history of the change of navigation parameters can be recorded during one or more playback processes. This may be used to particular advantage for market research, error search and the like. The second non-volatile memory is advantageously realized, as defined in claim 5, as a serial, cyclic buffer memory. The navigation parameters are temporally and serially written into the buffer memory. When the buffer memory is full, the oldest navigation parameters are erased so as to make room for new, updated navigation parameters. Such a serial, cyclic buffer memory is a simple and low-cost facility for storing temporal sequences of the navigation parameters. The further embodiment of the invention as defined in claim 6 has the advantage that the temporal sequences of the navigation parameters are externally readable and further processable.
The invention as defined in claim 7 is particularly suitable for apparatuses based on the DVD video standard. In accordance with the DVD video standard, 16 general parameters are provided as navigation parameters which have a length of 2 bytes each. These general parameters are available for the providers of record carriers so as to store the operation behavior of the user and to influence or control the behavior of the playback apparatus. The general parameters can be accessed by means of navigation commands. By storing the general parameters in the first non-volatile memory, information about a playback process of a record carrier can be stored. This information may be loaded from the non-volatile memory for playback at a later stage of the same record carrier or for playback at a later stage of another record carrier and used as a basis for the later playback process.
As defined in claim 8, the apparatus according to the invention is particularly suitable for apparatuses based on the High Quality Video Standard (HQ-Video). In accordance with the HQ-Video standard, at least 16 user parameters of 2 bytes each are provided as navigation parameters. According to the invention, these user parameters are stored in the first non-volatile memory and are thus available for playback at a later stage.
In accordance with the DVD standard, the general parameters are set to the value of zero at the start and the end of every playback process.
In accordance with the HQ-Video CD standard, the user parameters are undefined at the start and the end of every playback process.
The non-volatile storage of the navigation parameters thus represents a modification outside the DVD standard and the HQ-Video CD standard.
As defined in claim 10, the provider, i.e. the manufacturer and marketing representative of record carriers, can determine himself by means of the provider-characteristic information whether his record carrier is to be played back in accordance with the standard without non-volatile storage of the navigation parameters or whether the facility in the apparatus for non-volatile storage of the navigation parameters is to be used.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.